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Bloat Reclamation

Bloat Reclamation governs space reclamation, shaping system behavior under specific failure modes and workloads.

databases

Definition

Bloat Reclamation is a design property concerning space reclamation. It defines how the system behaves under specific conditions — what guarantees hold, what trade-offs apply, and how the mechanism interacts with related techniques. The property is only meaningful when its preconditions are met; outside those conditions it provides no benefit and may add cost.

Context and scope

Apply Bloat Reclamation when designing systems where space reclamation matters. It is most useful under partial failure, high load, or correctness requirements. Pair it with observability to verify the claimed behavior in production. Do not assume the property holds without testing the specific configuration and workload.

Common misconceptions

  • Bloat Reclamation eliminates all problems in its domain — it only bounds or shapes specific failure modes, not all pathologies.
  • Bloat Reclamation is free once you adopt the right tool — the property depends on configuration, workload, and failure pattern, not the product label alone.

Anti-patterns

  • Enabling Bloat Reclamation without measuring its cost in latency, availability, or operational complexity under production-like conditions.
  • Assuming Bloat Reclamation composes safely with other guarantees — combining mechanisms can introduce new failure modes or negate benefits.

Related concepts

Authoritative source

https://www.postgresql.org/docs/

What it is

Bloat Reclamation is a design property concerning space reclamation. It defines how the system behaves under specific conditions — what guarantees hold, what trade-offs apply, and how the mechanism interacts with related techniques. The property is only meaningful when its preconditions are met; outside those conditions it provides no benefit and may add cost.

When to use

Apply Bloat Reclamation when designing systems where space reclamation matters. It is most useful under partial failure, high load, or correctness requirements. Pair it with observability to verify the claimed behavior in production. Do not assume the property holds without testing the specific configuration and workload.

Common misconceptions

  • Bloat Reclamation eliminates all problems in its domain — it only bounds or shapes specific failure modes, not all pathologies.
  • Bloat Reclamation is free once you adopt the right tool — the property depends on configuration, workload, and failure pattern, not the product label alone.

Anti-patterns to avoid

  • Enabling Bloat Reclamation without measuring its cost in latency, availability, or operational complexity under production-like conditions.
  • Assuming Bloat Reclamation composes safely with other guarantees — combining mechanisms can introduce new failure modes or negate benefits.
  • Heap Bloat and Vacuum (vacuum-bloat)
  • Autovacuum and Dead Tuple Reclamation (autovacuum)